Patent GB-500107-A (GB)
Abstract: 500,107. Photographic recording of sighting adjustments ; tell-tale cameras. ZEISS IKON AKT.-GES. May 31, 1937-, No. 15122. Convention date, May 30, 1936. [Class 98 (il] [also in Croup XXI] An apparatus for use in bomb-dropping practice comprises an aiming or sighting apparatus and a kinematographic camera operatively connected therewith so that a photographic record can be obtained of the sighting adjustments made by the bomber. The sighting apparatus is carried by a triangular plate 1 and is mounted on a horizontal axle 2 so as to be capable of adjustment in accordance with a. longitudinal level 3. The, apparatus is also capable of adjustment by means of a knob 5 about a vertical axle 4 to compensate for lateral drift. The upper portion of the apparatus is provided with a horizontal frame 6 which carries three fixed scales, namely, an angle scale 7, altitude scale 8, and stop watch time scale 9, the altitude scale being graduated according to the reciprocal of the square root of the altitude, and the time scale according to the reciprocal of the time. A slide 10 carrying index marks 12, 13, 14 is mounted so as to be slidable along the frame 6. The slide 10 also carries the longitudinal level 3, a transverse level 15 and the back-sight in the form of a notch 11, which is capable of transverse adjustment by means of a knob 20. The lower end of the axle 4 carries a sight frame 16 provided with a run-in thread 17 parallel to the frame 6. and a transverse thread 18, it bead 19 which forms the fore-sight being located at the junction of the threads. An adjustable auxiliary bead 25 is also carried by the thread 17, and a vertical rod 21 carried on the frame 16 forms a prolongation of the run-in thread 17. The kinematographic camera 24 is mounted on the sighting apparatus in such a way that its optical axis always remains parallel to the sighting line 11 19. The lower part 28 of a housing 27 inside the camera forms a bearing for the camera, the upper portion of the latter being formed with a slotted guideway 26 in which engages a pin 23 attached to the slide 10. The housing 27 carries a fixed arcuate scale graduated in accordance with the scales 7, 8, 9 and an index line or mark carried by the camera housing 24 is moved over the scale when the camera rotates in consequence of adjustment made to the slide 10. The housing 27 also carries levels corresponding with the levels 3, 15 a stop watch and a sheet bearing the name of the bomber, the date. and so on, suitable optical means being provided for forming images of these on the film. Before commencing the flight at the target, a suitable auxiliary mark is selected near the target but sufficiently distant from it to enable the apparatus to be adjusted for dropping the bomb on the actual target after the auxiliary measurements have been made. The slide 10 is moved until the mark 14 is at the appropriate position on the altitude scale S. and a stop watch is started when the auxiliary mark on the ground comes into alignment with the notch 11 and bead 19. The scale 10 is then moved back to the zero position in which the sighting line is vertical and the watch is stopped when the auxiliary mark is vertically below the aircraft. The flight at the actual target is then commenced and the slide 10 is moved into the position in which the index 13 corresponds with the graduation on the time scale 9 in agreement with the time recorded during the flight over the auxiliary mark. The. bomb is released when the target crosses the sighting line 11-19 and the camera is then returned to the vertical position in order that the impact of the bomb may be recorded. The auxiliary bead 25 serves to indicate when the camera should be set in operation to record the aim on the target. In order to check the accuracy of the auxiliary time measurement, an electromagnetically controlled pointer may be projected in front of the film when the stop watch is started and withdrawn when the watch is stopped, the time being recorded on the film by the watch in the housing 27. The pointer is also projected in front of the film when the bomb release-lever is operated so that the instant of bomb release can be determined. The scale 7 is not utilized in the aiming operations and serves only to indicate the inclination of the line of sight at any time.